Dunham coefficients of 14N2 from CARS measurements of high vibrational states in a low‐pressure discharge

Spectroscopic constants of the X 1Σg+ ground state of 14N2 are deduced from CARS spectra recorded in a 4 Torr d.c. N2 glow discharge. Vibrational states up to ν = 14 have been observed but only the 11 lower levels which have a good signal‐to‐noise ratio have been processed. The Dunham constants that were deduced yield vibrational band centre positions in good agreement with those of Lofthus and Krupenie.